They have several different models to chose from. My model takes a 33oz gas cylinder. This will carbonate about 110L of cold water.
My original order included the carbonating machine, two gas cylinders and two carbonating bottles.
Soda Club's large gas cylinders are refillable. This is better than the most common type of soda siphon that uses one time use, individual charger cartridges for each Liter of water.
Soda Club sells the chargers with two cylinders so you can continue using the charger while waiting for an empty cylinder to be refilled. You can also purchase additional back up cylinders.
My order was delivered in 2 days. From what I understand, they have local folks as local distributors. These individuals will exchange your cylinder when it is empty. You do not need to ship, or mail it in anywhere. Place the order and you will receive a date when the delivery is scheduled. Leave the cylinder by your front door and it is magically full when you come back home. Reminds me of the Milk Man when I was a kid.
I suppose I might get faster service because I'm in San Francisco, an Eco friendly big city.
The system also came with two Soda Club bottles. These are heavy plastic bottles that I fill with (only) cold water and then mount on the machine and carbonate. There are suggestions on most Make your Own soda sites, to carbonate these full bottles of water and then add syrup to have a bottle of flavored Soft Drink.
I prefer to keep only water in the bottles. When I want a soft drink, I pour one ounce of syrup into a glass and fill it the rest of the way with carbonated water.
This way I can keep many different flavors of syrup on hand to make into a soft drink in an instant.
I also can drink the carbonated water as just clear seltzer, use a squeeze of lemon, or dilute fruit juices half and half. There are many suggestions to use carbonated water on stains (I haven't tested this).
If you would rather have full bottles of soft drinks, you can order additional charger bottles from Soda Club.
How to charge a liter of water
Warning - do not attempt to charge anything but water. Other liquids will cause a mess.
There is a line on the side of the bottle that shows the fill level.
Add cold filtered water to this line.
Screw the bottle onto the charger.
Depress the button on the top.
The charger will make a loud noise when fully charged. You can depress the button a few more times if you like more carbonation.
Unscrew the bottle from the charger and put the cap on.
Colder water holds more carbonation.
Machine service and maintenance
I've found the surface to be easy to wipe clean if I splatter it with something (It is on my kitchen counter). Because you only carbonate clean water, there is no cleaning of any kind necessary.
When the gas cylinder is empty:
* Unscrew the empty cylinder
* Replace with the full spare cylinder
* Put the cover back on the machine
* Put the empty cylinder in the box you just removed the new one from
* Order a gas refill by phone or on the internet
* On your delivery date, put your gas cylinder outside your door. Don't wrap or box it up.
* A full cylinder will be exchanged for the empty one
These cylinders are refilled over and over. This is so much better than the single use cartridges that are disposed or recycled.
BIG NOTE ABOUT MEASUREMENTS AND COSTSThere are huge possibilities for cost differences. I like a lightly flavored, lightly sweetened, highly carbonated soda. If you like a different style your costs and measurements will be different.
Costs change drastically with quantity also. I can only tell you what it costs for me.
*I rounded all Metric conversions to what I think is probably the common size used.
* * For example the 4oz bottle of concentrate actually contains 118mL. I used 120mL for the calculations.
* * A single serving in the U.S. is 16oz, that is 473mL. I used 450mL for the single serving conversion as I think that is the standard size used in many countries.
Please let me know if you find a large error. Small mismatches in conversions are probably because of the simplification of measures.